Riding the New York subway -never mind the temperature- take your pants off. Described as “an international celebration of silliness,” the unusual holiday is always planned for winter. This year it took place on Sunday, January 10. One day a year subway riders across the world get rid of their trousers and skirts to show off their new knickers and have fun as part of the “No Pants Subway Ride” day.

What started as a mere joke back in 2002 in New York by the Improv Everywhere prank collective, has now turned into an annual flash mob that brings together some 25 countries around the world , including the UK, Germany, Romania, the Czech Republic and Russia.